1. Technical Field
The present invention relates to a component test apparatus that performs tests on electronic components.
2. Related Art
Typically, various tests are performed on an electronic component such as a semiconductor chip when the electronic component is manufactured. The tests normally involve the use of a component test apparatus referred to as an IC handler. The component test apparatus has a plurality of transport devices that transport an electronic component, or a test subject, to predetermined positions (which are, for example, a loading position, a test position, and an unloading position) in the component test apparatus. Through the transport devices, the electronic component is supplied to the component test apparatus and arranged in a test socket provided in the component test apparatus before a test is carried out. After the test is completed, the transport devices remove the electronic component from the test socket and unload the electronic component from the component test apparatus. Specifically, for example, an electronic component to be tested is mounted on a shuttle by a loading robot serving as one such transport device. The shuttle then carries the electronic component to be tested to a position in the vicinity of the rest socket. At this position, a measurement robot (a transport hand) serving as another transport device holds the electronic component up from the shuttle, transports the electronic component to the test socket, and arranges the electronic component in the test socket. After the test is completed, the measurement robot holds the electronic component up from the test socket and mounts the electronic component onto the shuttle. The shuttle then transports the electronic component that has been tested to a position in the vicinity of a collection robot serving as another transport device. Afterwards, the collection robot then holds the electronic component and mounts the electronic component on a collection tray that corresponds to the result of the test.
Conventionally, there has been a demand for a component test apparatus that can perform a test on a great number of electronic components in a short time. To meet the demand, as a method of shortening the time required for the component test apparatus to carry out a test, Japanese Laid-Open Patent Publication No. 2002-148307, for example, discloses a method of decreasing the time needed for replacement of electronic components with respect to a test socket. According to the method, the component test apparatus, which is an IC handier, includes a plurality of test sockets aligned along a line and multiple pairs of transport hands. Each pair of the transport hands are arranged in such a manner as to straddle the corresponding one of the test sockets. Each of the transport hands has a suction mechanism that pulls and holds an electronic component and a pressing mechanism that presses the electronic component into a test socket. The hands of each pair of the transport hands, or a first transport hand and a second transport hand, operate independently from each ether. While the first transport hand is pressing the electronic component into the test socket, the second transport hand holding another electronic component that is to be pressed into the test socket subsequently is maintained in a standby state at a position maximally close to the first transport hand. This decreases the distance covered by transport of the electronic components when the electronic components are replaced with respect to the test socket. Accordingly, the total time required for the component test apparatus to conduct a test is shortened.
The time consumed by a test on an electronic component using a test socket varies depending on the content of the test. In some cases, the time required to transport the electronic component, which is, for example, the time required to unload the electronic component to a shuttle after the test is completed or the time required to hold the electronic component up from the shuttle and move the electronic component to a position in the vicinity of the test socket before the test is started, is longer than the time consumed by the test on the electronic component. In these cases, the method of the aforementioned publication cannot always shorten the total time necessary for completion of the test. In other words, the test on the electronic component that has been arranged in the test socket by the first transport hand may end before transport of the subsequent electronic component by the second transport hand is completed. In this case, the second transport hand cannot be held in a standby state in the vicinity of the first transport hand. Further, the transport hands unload and load the electronic components each time the test is performed. As a result, operation involving such unloading and loading imposes a limit on shortening the total transport time.